The Ba'ku language was the language of the Ba'ku and presumably their Ka'bu forebears. The word ba'ku itself meant "the Peaceful" (TNG novelization: Insurrection) or "new beginning" (Last Unicorn RPG module: Planets of the UFP), while son'a meant "Science Movement". The Ba'ku equivalent of "captain" or "commander" was ahdar. The language, at least as it was used by the Son'a, had no word for "death", with the concept being expressed in whispered euphemisms. (TNG novelization: Insurrection)